#include <iostream>
#include <string>

using namespace std;

class Solution {
public:
    string replaceSpace(string s)
    {
        string s1;
        for (size_t i = 0; i < s.size(); ++i) {
            if (s[i] == ' ') {
                s1 += '%';
                s1 += '2';
                s1 += '0';
            } else {
                s1 += s[i];
            }
        }
        return s1;
    }
};

int main()
{
    cout << "Hello World!" << endl;
    return 0;
}
